Clare Balding should be spending New Year’s Eve, glass of Krug in hand, toasting what has been, for her, a truly vintage year.

Instead, you’ll find her down in Gloucestershire with a Channel 4 camera crew, preparing for her coverage of the new year’s meet at Cheltenham races. “Why not start the year as I mean to continue?” she asks.

Balding isn’t the type to put her feet up. In the past few weeks, television’s girl of the moment has hosted the BBC’s Sports Personality of the Year and delivered a four-part retrospective of 2012 on Radio 2. And in the coming weeks she will be fronting Britain’s Brightest, a brand new Saturday night light-entertainment show that makes its debut on BBC One next weekend.

Such is Balding’s overbooked diary that interviews with her are conducted on high-speed trains, hurtling between engagements, on mobile phones or, in this case, in the back of a car. Balding, 41, is on her way back to London from Hungerford after a day signing copies of her best-selling autobiography, My Animals and Other Family.

She has spent the afternoon engaging with the public, inscribing messages on the flyleaf of her book, and should be shattered. Instead, she’s upbeat and bubbly, with a 100-watt energy lighting up her blue-grey eyes.

“When you’re living the life that I am right now, you don’t complain about the demands on your time. I’m buoyed up by the fact that it has been such an amazing year, and I am loving every minute of it. I feel on a pretty constant high, so tiredness tends not to come into it.”

The amazing year has included her acclaimed coverage of this summer’s Olympics and Paralympics, praised by the public and press alike for her knowledgeable and engaging style. “It was the first time they wrote about me without even mentioning the word 'lesbian’,” she laughs.

Earlier this month, that coverage earned her an Achievement of the Year at the Women in Film and Television awards, to add to the Best Biography honour bestowed at November’s National Book Awards. “Can you believe I even beat Salman Rushdie in that category? It feels amazing.”

Balding has been fêted and fawned over, decorated and generally elevated to something that is beginning to look suspiciously like National Treasure status. At one point she found herself next to Justin Bieber on the sofa of The Jonathan Ross Show. “Bieber didn’t have a clue who I was, of course, and I thought it might be a laugh to tell him I was a scientist who invented The Mobot – which I did, of course.

“But seriously, pre-Olympics I’d never have considered myself hot enough property for The Jonathan Ross Show. And you do think, 'How did this happen?’”

What it probably boils down to, she says, is something rather simple: a growing desire on British television for substance and for experienced, capable presenters who have done their homework.

Balding sensed a sea-change after the BBC’s coverage of the Queen’s Jubilee, which received as much criticism as its Olympics coverage received praise. “You think back to the River Pageant, in particular, and people said, 'Hang on a minute, we don’t want the light entertainment treatment. We want to be informed and interested, we want presenters who are well-prepared and know their stuff.

“Yes, the BBC should entertain, but in doing so they’d moved too far from their remit to educate, too, and viewers didn’t like it. So maybe when it came to the Olympics there was an appreciation of the way I like to do things.”

Her modus operandi, developed over 16 years as a presenter, involves basic but cardinal rules. “I get to know the athletes, so they’re comfortable and pleased it’s me who’s interviewing them. I also do a lot of background work so that I’m informed and I know what questions to ask.

“People commented on how messy my desk was during the Olympics and, yes, it was covered with running orders, start and finish sheets. Mountains of homework. The hard work was on show but that’s what viewers like.

“You could take me out of the equation altogether if you like. It wasn’t a question of, 'We want Clare.’ It was more, 'We want it the way Clare does it.’ And if that’s created a fashion for factually loaded content presented in a palatable way, then I’m thrilled because I do try to be all about substance.”

That substance could well be about to revolutionise Saturday night prime-time viewing, too. Britain’s Brightest occupies a slot previously vacated by ratings-grabbers like The Voice, but it is not about the contestants’ ability to sing or dance or twinkle for the camera. “It’s an exciting departure, both for myself and for the BBC, and a step in the right direction towards intelligent family viewing,” she says. “And the thing is to hook people in and keep them interested, and I hope it does that because you do end up marvelling at how brilliant some people’s brains are.”

Britain’s Brightest is a knock-out tournament with 24 contestants who have qualified through a nationwide audition process – “ordinary people with extraordinary minds”. Rather than straightforward IQ tests, the show – a cross between The Krypton Factor and Test the Nation – will feature a series of demanding challenges and puzzles staged both in the studio and on location in Salford, where the series is filmed. Everything from emotional intelligence to the speed at which contestants can process information will be tested to the limit, before the best all-rounder is crowned.

“The contestants are super-bright in different ways,” says Balding. “Some are academically clever or numerically gifted, others have brilliant memories or observational skills, or are able to cleverly anticipate the answer to a question by lateral thinking.

“I have always said that 'facts are my friend’, but knowing things doesn’t make you clever. It’s so much more complicated than that, which is why I’ve always been fascinated by intelligence and how our brains work, and how they can be improved.

“Because of my interest in sport, too, I wanted to know if you could keep the brain fit and working for you in the same way as the body, and it was great to meet the contestants who all have their own theories. Interestingly, these people don’t necessarily have A stars at A-level. Often, in fact, they don’t have good exam results at all.”

Balding is one of Britain’s brightest herself. She was head girl at Downe House in Berkshire, and graduated from Newnham College, Cambridge, where she was President of the Union Society, with a 2:1 in English literature.

A former amateur flat jockey, she recalls her childhood growing up in the saddle at Kingsclere, the Newbury stables where her father, Ian Balding, trained legendary champions such as Mill Reef and several of the Queen’s horses.

“It was an extraordinary upbringing,” she says. “And though I didn’t see it then, I do now. It’s not normal, for example, to have the Queen showing up for breakfast. I’m not showing off about it in my book, but it was my reality.”

When it was published, some reviewers picked up on Balding’s honest assessment that her parents’ love of animals – and horses in particular – left her sidelined on occasions. The honesty was combined with humour and affection. “But you do worry whether your parents are still going to love you after you’ve pointed out their faults,” she says.

At the time of publication, one interviewer in particular painted a poor picture of her father which, she says, did not reflect her feelings for him.

“I rang him to warn him and also to say that it was going to be a funny old summer with people saying all sorts of things, but I wanted him to know how much I love him.

“He said, 'Well I think the book is wonderful and I’m not having anyone saying otherwise. Don’t even think about it. Just crack on.’”

Her partner, the radio newsreader Alice Arnold, has been equally supportive. “Alice read every chapter as I wrote it and read the book again in draft form. I listen to her advice because she is very astute and almost always right.”

Arnold has been a hugely stabilising influence during the 2012 rollercoaster year. “The great thing about Alice is that she isn’t impressed by a lot of things, so it means that I’m not either. She is very good at letting me enjoy being on the wave, but she’ll also say, 'It’s time to calm down now; the dog needs a walk.’ She is totally encouraging but also pragmatic and realistic.”

They became civil partners in 2005 and their legal union is important to both of them. “It legitimises our relationship and it binds us by law. We always say to each other now, 'It’s illegal for you to leave me!’”

They don’t describe themselves as ''married’’. “Well, there isn’t marriage for gay people yet. And until there is, we won’t say it. But, yes, our civil partnership matters because it makes it real, and if you don’t acknowledge your relationship in public, or you’re gay and you’re in the closet, or you’re with someone and you’re not quite ready to introduce them to everyone, then that relationship isn’t real. But as soon as it becomes public it is. And the nice thing is that Alice and I now get invited to everything together.”

Since Balding’s stock shows no sign of diminishing, there will be plenty more invites in the post. Aside from Channel 4 Racing and Britain’s Brightest, from January she will also have her own Radio 2 show on Sunday mornings.

So much success has come her way since the day, three years ago, that she discovered she had thyroid cancer. Cancer gives you perspective, she says. Confronted with the Olympics last summer she had felt underprepared. “I’d been so busy all year, and the Olympics were looming like a brick wall. But illness teaches you to relax a bit. You know, it’s not the end of the world if you mess up. And, actually, it was all right on the night, wasn’t it?”

Balding is not one for self-pity, either. “A lot of interviewers are looking for the dark side,” she concludes. “They want to know about the depths of your despair and fear. But the truth is, I don’t have it. It’s just not there.

“I also think, 'What’s wrong with the sun shining most days?’ It’s the way I was raised and the way I am built – and I’m really very thankful for it.”